1. Field of the Invention
The present invention relates to an ultrasonic diagnosis apparatus, image processing apparatus, and image processing method for the accurate extraction of rotational components in evaluating motion information concerning the rotation of a tissue using a three-dimensional image.
2. Description of the Related Art
It is very important for the diagnosis of a living tissue such as cardiac muscle to objectively and quantitatively evaluate the function of the tissue. Recently, various quantitative evaluation methods using ultrasonic diagnosis apparatuses and the like have been attempted mainly on the heart as an example. For example, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-250804, there has recently been commercialized a technique called speckle tracking, which is a technique of calculating local wall motion information such as displacement or strain while performing local pattern matching in images. In addition, Jpn. Pat. Appln. KOKAI Publication No. 2007-44499 discloses a technique of obtaining three-dimensional rotation or twist as wall motion information in a short-axis plane.
There has not currently been established any specific method of obtaining rotational angles in a space accompanied by three-dimensional position tracking in quantitative evaluation of the rotational motion of a tissue. For example, Jpn. Pat. Appln. KOKAI Publication Nos. 2003-250804 and 2007-44499 described above define only a rotational angle in a short-axis plane (two-dimensional plane).
In the calculation of rotational angles in a space accompanied by three-dimensional position tracking, the following problems arise. That is, when three-dimensional position tracking is to be performed, a surface for the definition of a rotational angle is not necessarily limited to a plane but may be a curved surface. In addition, a region whose rotational angle is to be obtained may move in a direction perpendicular to a surface for the definition of a rotational angle. Quantitatively evaluating the rotational motion of a tissue without the consideration of these situations will result in overestimation of a rotational angle when there is unevenness in a shortening motion in the circumferential direction or a spatially uneven motion component in a direction perpendicular to the rotating direction accompanying a shear motion component.